As for determining which animals have been strangled and not drained of their blood, we must understand that the focus was on the quantity of blood remaining in the meat of the animal. It was not the fact that the animal was strangled that kept it from being eaten, but the fact that it was never drained of its blood.
The Eocene constitutes the middle part of the Paleogene period (65-23 million years ago), preceded by the Paleocene and succeeded by the Oligocene epoch (34-23 million years ago); all of these periods and epochs were part of the Cenozoic Era (65 million years ago to the present).
(Beginning of earth - 544 million years ago) All geologic time before the beginning of the Paleozoic era. This includes about 90% of all geologic time and spans the time from the beginning of the earth, about 4.5 billion years ago, to 544 million years ago.